The present invention relates generally to the field of pneumatic equipment and in particular to an air supply that does not induce side forces on a pneumatic tool.
Pneumatic tool assemblies (comprising a pneumatic tool, a housing, and various support functions such as air supply and regulation) are commonly deployed on robots, computerized numerical control (CNC) equipment, and the like, to perform routine and repetitive tasks. One such task is the deburring of the edges of machined or cast parts. In a typical deburring operation, a deburring tool is directed along a path around the edge of a part or object that is to be deburred.
For several reasons, robotically or numerically controlled deburring tools require some displacement compliance. The programmed path of the robotic arm or numeric equipment may not exactly coincide with the shape or contours of the surface to be deburred. Additionally, the edge or surface of the part being deburred may include cavities or protrusions that deviate from the anticipated path of the tool. Another factor requiring compliance in the deburring tool is variation in the fixtures, or structures that hold the parts while they are being deburred. Fixture variations may result in the surfaces of the parts to be deburred being misaligned with the programmed path of the deburring tool.
Ideally, the compliance force of a deburring tool should be the same in all directions. In practice, uniform compliance is difficult to achieve. For example the weight of a tool, its housing and possibly the actuating arm or member to which it is attached, results in a different compliance response to the same force exerted on the tool from the top and the bottom. The compliance force of a deburring tool may be largely decoupled from its housing and support by, for example, gimbal-mounting the tool within its housing or supporting it by other means, preferably at or near the center of gravity of the tool. A two-axis gimbal allows the tool to move freely in any radial direction, and mounting the gimbal at the tool's center of gravity largely obviates the weight of the tool as a compliance force factor.
However, another factor that adversely affects compliance uniformity is the supply of pressurized air to drive the pneumatic tool. If the air is supplied to the tool at any non-axially-aligned point, it induces a force on the tool that must be countered to maintain the axial alignment of the tool within its housing. This compensation causes a non-uniform compliance response to forces in that direction, with respect to any other direction. Supplying the air axially, such as at the rear of the tool assembly, is impossible in many applications, as this is the preferred mounting point of the tool assembly to a robot arm or numerically controlled equipment, which may not be configured to supply the air.